Bill Gates gives away 64 million Microsoft shares in largest donation since 2000.

Microsoft co-founder Bill Gates is reducing his stake in the company to just 1.3 percent, after holding 24 percent of the software maker back in 1996.

In a filing to the Securities & Exchange Commission (SEC) on Monday, Gates revealed he’s donating 64 million shares of Microsoft worth a total of $4.6 billion. It’s a huge donation, and Bloomberg reports that it’s the biggest since he gave away $16 billion worth in 1999 and $5.1 billion of shares in 2000.